ASTM D6431-2018 pdf free download

ASTM D6431-2018 pdf free download.Standard Guide for Using the Direct Current Resistivity Method for Subsurface Site Characterization
1. Scope
1.1 Purpose and Application: 1.1.1 This guide summarizes the equipment, field procedures, and interpretation methods for the assessment of the electrical properties of subsurface materials and their pore fluids, using the direct current (DC) resistivity method. Mea- surements of the electrical properties of subsurface materials are made from the land surface and yield an apparent resistiv- ity. These data can then be interpreted to yield an estimate of the depth, thickness, voids, and resistivity of subsurface layer(s). 1.1.2 Resistivity measurements as described in this guide are applied in geological, geotechnical, environmental, and hydrologic investigations. The resistivity method is used to map geologic features such as lithology, structure, fractures, and stratigraphy; hydrologic features such as depth to water table, depth to aquitard, and groundwater salinity; and to delineate groundwater contaminants. General references are, Keller and Frischknecht (1), 2 Zohdy et al (2), Koefoed (3), EPA(4), Ward (5), Griffiths and King (6), and Telford et al (7). 1.1.3 This guide does not address the use tomographic interpretation methods, commonly referred to as electrical resistivity tomography (ERT) or electrical resistivity imaging (ERI). While many of the principles apply the data acquisition and interpretation differ from those set forth in this guide. 1.2 Limitations: 1.2.1 This guide provides an overview of the Direct Current Resistivity Method. It does not address in detail the theory, field procedures, or interpretation of the data. Numerous references are included for that purpose and are considered an essential part of this guide. It is recommended that the user of the resistivity method be familiar with the references cited in the text and with the Guide D420, Practice D5088, Practice D5608, Guide D5730, Test Method G57, D6429, and D6235.1.2.2 This guide is limited to the commonly used approach for resistivity measurements using sounding and profiling techniques with the Schlumberger, Wenner, or dipole-dipole arrays and modifications to those arrays. It does not cover the use of a wide range of specialized arrays. It also does not include the use of spontaneous potential (SP) measurements, induced polarization (IP) measurements, or complex resistivity methods. 1.2.3 The resistivity method has been adapted for a number of special uses, on land, within a borehole, or on water. Discussions of these adaptations of resistivity measurements are not included in this guide. 1.2.4 The approaches suggested in this guide for the resis- tivity method are the most commonly used, widely accepted and proven; however, other approaches or modifications to the resistivity method that are technically sound may be substituted if technically justified and documented. 1.2.5 This guide offers an organized collection ofinforma- tion or a series ofoptions and does not recommend a specific course of action. This document cannot replace education or experience andshould be usedin conjunction with professional judgements. Not all aspects ofthis guide may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy ofa given professional service must be judged, nor should this document be applied without consideration of a project’s many unique aspects. The word “Standard” in the title ofthis document means only that the document has been approved through the ASTM consensus process. 1.3 Units—The values stated in SI units are to be regarded as standard. No other units ofmeasurement are included in this standard. Reporting of test results in units other than SI shall not be regarded as nonconformance with this test method.1.4 Precautions: 1.4.1 It is the responsibility of the user of this guide to follow any precautions in the equipment manufacturer’s rec- ommendations and to consider the safety implications when high voltages and currents are used. 1.4.2 Ifthis guide is used at sites with hazardous materials, operations, or equipment, it is the responsibility ofthe user of this guide to establish appropriate safety and health practices and to determine the applicability ofregulations prior to use.